Peelable protective films are used to protect rubber, metal, plastic, or other articles so that their surfaces are not contaminated, scatched, corroded, or otherwise damaged during their shipment and storage. After they have served their purpose, they can be readily peeled away from the substrate.
Peelable protective films of the type described above are conventionally made of polyvinyl- or polyolefin-based polymers such as polyvinyl chloride, high-density polyethylene, low-density polyethylene, polypropylene, and ethylene/vinyl acetate copolymers.
Japanese Patent Publication No. 45974/83 describes a polyolefin-based peelable protective film made of an ethylene/1-butene random copolymer. Further, Japanese Patent Publication No. 47993/84 proposes an invention of a dual layered film formed of a layer of a mixture of an ethylene/ethyl acrylate copolymer and an ethylene/vinyl acetate copolymer and a layer of a polyolefin. The films disclosed in the above-referenced patents are chiefly intended to protect the surfaces of metal articles, and the property that is principally required of these films is good adhesion to the substrate.
In the case that substrates to be protected have tackiness or adhesion as in rubber articles, there have been proposed methods in which the substrates themselves are coated with antiblocking compositions such as hydrocarbon-based resin compositions or anionic or nonionic surfactants (see Japanese Patent Publication Nos. 10860/76 and 50047/77 and Japanese Patent Application (OPI) No. 78945/77). The term "OPI" as used herein means "unexamined published application." However, there have been no reports at all that a film per se is used as a protective film having good peelability to such tacky substances. Therefore, one has had to be satisfied with use of low-density polyethylene films or other films as a protective film of, e.g., a rubber veil, though they are poor in peelability.